The Influence of Reaction Kinetics on Polyurethane/Vinyl Ester Resin Interpenetrating Polymer Networks

Abstract

Polyurethane/poly(vinyl ester resin)(butyl methacrylate) Interpenetrating Polymer Network (PU/VER(BMA) IPN) materials were synthesised at room temperature by polymerising butyl methacrylate as a comonomer with simultaneous interpenetration. The curing process of these IPNs was dynamically traced and semi-quantitatively analysed by Fourier transform infrared spectroscopy (FT-IR) and the kinetics of their formation with different PU catalysts and VER initiators was studied. The results showed that when the amounts of stannous octoate and BPO respectively were 0.5wt.% of PU and 0.67wt.% of VER, the reaction rates of the monomers were close, the conversions of the monomers were high and these amounts were optimised. The influence of the kinetics on the microstructure and damping properties of the IPNs was detected by Transmission Electron Microscopy (TEM) and by Dynamic Mechanical Analysis (DMA). The results showed that with the appropriate amount of the polyurethane catalyst stannous octoate and VER initiator BPO, the PU/VER(BMA) IPN showed a multiphase microstructure containing some finer phase domains having nanometre domain sizes, together with good damping properties (a broad damping plateau and high tanδ). When the amount of stannous octoate or BPO was increased or decreased, the IPNs presented an unfavourable microstructure and poor damping properties. The relationship between the kinetics, microstructure and damping properties was analysed further.